Human activity such as agriculture, irrigation, industrial processes, sea transport and sewage disposal can impact on the components and processes of the water cycle in a number of ways — consider the impact of power generation through hydroelectric dams, for example.
Where groundwater is acknowledged, it is often seen as a static, unchanging component of the water cycle. At times, students also underestimate the impact of human activities on the water cycle. Before starting teaching the water cycle, students need to understand some of the basic scientific ideas underpinning the concept of the Earth system and its four subsystems.
Students could engage in the activities Building a water cycle and Constructing an aquifer model , before tracing the many possible paths of an imaginary water molecule within the water cycle in order to identify relevant processes and components. Such an activity can also highlight the role of time in the cycle and teach students an appreciation that materials move at different rates at any given time. An extension activity could be to learn more about parts of the water cycle and how it affects the subsystem of system Earth by exploring the article Humans and the water cycle.
Teacher PLD. Add to collection. Go to full glossary Add 0 items to collection. Download 0 items. Twitter Pinterest Facebook Instagram. It is accepted science that the Earth is an open system for energy. This delicate balanced transfer of energy maintains the surface temperature at a level that is suited to the forms of life that have evolved and currently exist.
From the Holocene to the Anthropocene. Video signpost. How the Earth works. The Earth is an open and closed system. Matter changes form, but never disappears. All materials disperse and spread out if not contained. How the biosphere works. Geological and geochemical cycles. Although liquid water is present around the globe, the vast majority of the water on Earth, a whopping All of the liquid water on Earth, both fresh and salt, makes up the hydrosphere, but it is also part of other spheres.
For instance, water vapor in the atmosphere is also considered to be part of the hydrosphere. Ice, being frozen water, is part of the hydrosphere, but it is given its own name, the cryosphere. Rivers and lakes may appear to be more common than are glaciers and icebergs, but around three-quarters of all the fresh water on Earth is locked up in the cryosphere.
Not only do the Earth systems overlap, they are also interconnected; what affects one can affect another. That precipitation connects the hydrosphere with the geosphere by promoting erosion and weathering , surface processes that slowly break down large rocks into smaller ones.
Over time, erosion and weathering change large pieces of rocks—or even mountains—into sediments, like sand or mud. The cryosphere can also be involved in erosion, as large glaciers scour bits of rock from the bedrock beneath them. The geosphere includes all the rocks that make up Earth, from the partially melted rock under the crust, to ancient, towering mountains, to grains of sand on a beach.
Both the geosphere and hydrosphere provide the habitat for the biosphere, a global ecosystem that encompasses all the living things on Earth. It contains a wide range of organisms, including fungi, plants, and animals, that live together as a community. Biologists and ecologists refer to this variety of life as biodiversity.
All the living things in an environment are called its biotic factors. The biosphere also includes abiotic factors, the nonliving things that organisms require to survive, such as water, air, and light. The atmosphere—a mix of gases, mostly nitrogen and oxygen along with less abundant gases like water vapor, ozone , carbon dioxide, and argon—is also essential to life in the biosphere.
Atmospheric gases work together to keep the global temperatures within livable limits, shield the surface of Earth from harmful ultraviolet radiation from the sun, and allow living things to thrive.
One specific example of interaction between all the spheres is human fossil fuel consumption. Deposits of these fuels formed millions of years ago, when plants and animals—all part of the biosphere—died and decayed. At that point, their remains were compressed within Earth to form coal, oil, and natural gas, thus becoming part of the geosphere.
Now, humans—members of the biosphere—burn these materials as fuel to release the energy they contain. The combustion byproducts, such as carbon dioxide, end up in the atmosphere.
There, they contribute to global warming, changing and stressing the cryosphere, hydrosphere, and biosphere. The audio, illustrations, photos, and videos are credited beneath the media asset, except for promotional images, which generally link to another page that contains the media credit.
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